The present invention relates to a cleaning apparatus that cleans a cleaning target (a subject to be cleaned), such as a water pipe, using compressed air.
For example, Japanese Examined Patent Publication No. 2-37236 discloses a pipe cleaning apparatus for cleaning a pipe as a cleaning target. The pipe cleaning apparatus has a compressor, a reservoir tank that is connected to the compressor and reserves compressed air, and an electromagnetic valve that communicates with the reservoir tank via a pressure adjustment valve. The pipe cleaning apparatus repeats opening and closing the electromagnetic valve according to a predetermined open time and close time during a predetermined operation time. The pipe cleaning apparatus has an air spurt timer, which determines the open time in order to adjust the expelling amount of compressed air, and an air stop timer, which determines the close time in order to adjust the expelling period for the compressed air. Further, the pipe cleaning apparatus has a general work timer that sets the operation time.
The compressed air that is produced by the compressor is temporarily reserved in the reservoir tank, and then is fed to the electromagnetic valve from the reservoir tank. Thereafter, as the electromagnetic valve is opened, compressed air is fed from the electromagnetic valve to a pipe to be a cleaning target. The electromagnetic valve alternately repeats being opened and closed according to the open time and the close time to intermittently expel the compressed air to the pipe. The compressed air that has been expelled intermittently causes a water hammer action in the pipe, thus removing an adhered matter, such as an oil component, rust, or dust, adhered to the inner surface of the pipe. The pipe cleaning apparatus is automatically operated during the operation time set by the general work timer and is automatically stopped after the operation time elapses.
In case of the conventional pipe cleaning apparatus, as compressed air is reserved in the reservoir tank, reduction in pressure is prevented during cleaning. The operation time is set only by the general work timer regardless of the capacity or the like of the compressor. In the actual cleaning work, however, it is very likely that the operational state of the compressor varies according to the work conditions, such as the temperature at the cleaning spot and the supply electricity. In this case, the compressed air may be expelled to a pipe in a state where the pressure of the compressed air to be expelled to the pipe is less than a sufficient value. It is therefore necessary for a worker to always observe the pressure of the compressed air and to stop the pipe cleaning apparatus or readjust the pressure of the compressed air every time it drops. As a result, the cleaning work cannot be simplified, thereby bringing about a reduction in working efficiency.